It is well known in the art to provide a door with a deadbolt lock. Such locks are generally provided where security is a concern, such as the door of a home, business, or hotel room. The deadbolt is mounted above the usual doorknob that actuates the less secure spring loaded latch. The deadbolt lock is operable by a key on the outside. It may be operable without a key on the inside by a simple knob. This enables escape in an emergency without a key. The knob is elliptical in shape so that a user can visually determine whether the deadbolt is locked or unlocked. The long axis of the ellipse is generally vertical when the bolt is in the locked position. When a person is secure behind a deadbolt locked door, that security may be breached by someone with a key, or someone with means to retract the bolt.
U.S. Pat. No. 7,284,400 issued Oct. 23, 2007 to one of the applicants discloses a device to further ensure that someone with a key or other means to operate the deadbolt could not move the bolt enough to open the door. A first end of the device has a passage to receive the deadbolt knob when the bolt is in locked position and the long axis is vertical. As the knob is rotated, the device is so shaped and dimensioned that it also is rotated, until a portion of the device is forced against a rigid element, such as the door frame, or jamb, that prevents further rotation. Unfortunately, there are deadbolts that do not present the long axis of the knob in vertical position when the bolt is in locked condition. The long axis of the knob may be horizontal or plus or minus 45 degrees from the vertical when in locked condition. In many of those situations, the device of the prior art will not function. Another problem is encountered with some doors that swing inward to open. When they have a thick bezel at the base of the deadbolt lock knob, the bezel may hold the device of the prior art off the door surface far enough that it swings past the door frame, thereby allowing the deadbolt to open.